1 Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada. Electronic address: johanna.harrison@mail.mcgill.ca.
2 Wolfson College, University of Cambridge, Cambridge CB3 9BB, United Kingdom; MRC/BHF Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Strangeways Research Laboratory, 2 Wort's Causeway, Cambridge, CB1 8RN, United Kingdom.
3 Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada.
4 Department of Exercise Science, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4 B 1R6, Canada.

Respiratory and hemodynamic contributions to emotion-related pre-syncopal vasovagal symptoms.

Biol Psychol. 2017 07;127:46-52

Authors: Harrison JM, Gilchrist PT, Corovic TS, Bogetti C, Song Y, Bacon SL, Ditto B

Abstract

Vasovagal reactions are conventionally understood as resulting from systemic changes in cardiovascular activity; however, there exists a complementary perspective focused on specific changes in cerebral vasoconstriction associated with hyperventilation-induced hypocapnia. The present study investigated the role of cardiovascular and respiratory activity in self-reported pre-syncopal vasovagal reactions to a surgery video in a sample of 49 healthy women. Participants who indicated more previous real-life episodes of dizziness reported experiencing significantly more symptoms in the laboratory consistent with a vasovagal response. They also showed lower total peripheral resistance and higher pre-ejection period in general, suggesting lower sympathetic nervous system activity. Significant decreases in end-tidal carbon dioxide (PETCO2) occurred during the surgery video among susceptible participants, without significant increases in respiration rate. Further, participants who experienced reductions from the neutral video in PETCO2, systolic blood pressure, or both, reported vasovagal symptoms during the surgery video. The results suggest that patterns of respiration associated with decreases in PETCO2 may contribute to vasovagal symptoms reported in non-clinical groups as well as those with blood-injection-injury phobia and are associated with susceptibility to dizziness.

PMID: 28456564 [PubMed - indexed for MEDLINE]